Grate structure for boilers



nUPoN-r @RATE sTRuc'rRE Fon' Bolwnnns Filed may); 1924 Patented Dee, 23, 1924.

UNI'E'E nazaire E QFHCE.

EDGARD DUPONT, OF ANTWERP, BELGIUM.

GRATE STRUCTURE FOR BOILERS.

Application filed May 12, 1924. Serial No. 712,676.

To @ZZ whom t may concern.

Be it known that I, EDGARD DUPONT, a subject of the King of the Belgians, residing at Antwerp, Belgium, 56 Rue Robert Mols, have invented new and useful Improvements in Grate Structures for Boilers, of which the following is a specification.

The present invention relates te an improved grate-structure with fire bridge, made entirely of cast iron and applicable to the furnaces of steam boilers employing solid fuel, and more particularly to marine boilers.

The structure according to the invention substantially comprises a horizontal grate composed of a plurality of removable and interchangeable grate-bars, of cuneiform cross section and of sinuous or waved conformation in the longitudinal direction, resting at their ends on suitable grate-bar bearers, in combination with a fire bridge comprising a plurality of removable and interchangeable grate-bars curved to form a quarter of a circle, of suitable cross section and having cut away portions forming corrugations along a portion of the length of their sides, which grate-bars are arranged side to side and bear at their lower and up per ends respectively on a dead plate which also forms a grate-bar bearer for one end of the horizontal grate, and on the upper edge of a supporting plate arranged substantially at right angles to the said dead plate, the said grate-bars of the fire bridge having recesses formed in the edges of their upper portion so as to constitute by their juxtaposition apertures for the passage of cooling air. The invention further comprises the provision of means to lockthe fire bridge grate bars in position or disengage them at will, by means of a flat locking bar passing through a slot in the supporting plate for the upper ends of the said grate-bars, and capable of being operated through the medium of suitable rod connections.

In order that the invention may be more readily understood, an embodiment thereof is, by way of example only, described in detail hereunder by reference to the accompanying diagrammatic drawings, in which:

Figure l is a longitudinal section through a grate-structure inaccordance with the invention,

Y tral lugs 4, to allow free dilatation or Figure 2 is a corresponding plan, a portion of the grate-bars being removed, and

Figures 8, t and 5 show the transverse section of a grate-bar,taken respectively on the line lll--HI, IV-IV and V-V of Figure l.

Referring to the said drawings, the struc ture according to the invention comprises a grate-bar bearer 1 adapted to receive the ends 2 of the grate-bars constituting the horizontal grate adjacent the furnace front.

The horizontal grate is flat and forms a' single panel comprising a certain number of separate removable grate-bars 3 having a sinuous or waved shape in the direction of their length, as illustrated by `Figure 2. These bars 3 are larranged loosely side to side, with the necessary clearance between their ends 2 and 2 and between their ceneXpansion in all directions. These bars 3 have a cuneiform cross section so that the whole forms a grate-plate for a furnace with forced draught by suction of air.

The described arrangement allows the cleaning of the furnace to be effected easily by the introduction of a poker-iron with pivoted hook in the spaces 5 between the bars 3 in order to break and destroy the cakes, masses of slag and other residues of combustion. Moreover the particular sinuous or wave-d conformation of the gratebars enables the effective surface of the grate to be appreciably increased by increasing the length of the spaces 5 between the bars while maintaining the width of such spaces, so that the draught will be intensiporization will be obtained.

The rear ends 2 of the grate-bars 3 rest on a grate-bar bearer 6 which is integral with a dead plate 7 forming a portion of a casting 8 which is of such a cross section as to provide also a support 9 for the lower ends l1 of the fire bridge grate-bars 10. The rebridge comprises a quarter `circle grate composed of a certain. number of curved removable grate-bars 10 arranged loosely side to side and havingcut away portions 'forming corrugations along a portion of the length of their sides, .as illustrated by Figure 2. These fire bridge bars a supporting plate 12 arranged substantially at right angles in relation to the dead plate 7 and extending along the whole length of the lire bridge, and the said bars 10 are maintained in position through the engagement of a lug 13 provided under their upper ends 11 in a corresponding longitudinal groove 1&1 provided in the upper edge ot' the supporting plate 12.

The dead plate T posseses two openings 15 for the admission of air under the gratebars of the lire bridge this air, arriving from the ashpit, passing through the lire bridge grate under the influence of the draught.

Seen incross section, the upper portion ot the grate bars 10 has a shape recalling that of the head of a wood screw or et a nail asillUstra-ted by Figures 4 and 5 respectively, so as to set up a suction ot air to bring the latter into contact with the unburnt gases in the combustion chamber, in order to ensure the ignition thereof and thus to increase further the eiiiciency ot the generator. Close to their upper ends 11', the grate-bars 10 moreover have a series ot recesses formed in their edges so as to constitute by their juxtaposition small circular apertures 16 tor the passae'e ot cooling air.

The means provided to loch the gratebars 10 in position comprise a locking bar 17 ot flat section, passing through a longitudinal slot 18 cut in the supporting plate 12. This flat locking bar 17 is secured to the upper ends of a pair ot rods 19 fixed on a horizontal bar QOcapa-ble ot pivoting in small bearings 21 provided on the supporting plate 12. At their lower ends the said rods 19 are pivotally connected to an operating rod 22 extending under the furnace towards the furnace front, :tr-om where it may be operated by means ot an operating handle 28 with which it is provided. The flat locking bar 17 is capable of engaging in suitable notches or recesses 24 cut into the ends 11 ot the bars 10, so that by operating the rod 22 the said grate-bars may be locked in the position required tor a goed ethciency byengaging the locking bar 17 in the recesses 24, or may be rendered tree by disengagingV the saidlocking bar 17 troni the said recesses 24. The grate-bars 10 being thus rendered Jfree, the removal and the renewal of single grate-bars may be readily elitected, and an intermediate grate-bar may be added without it being .necessary to remove the adjacent bars.

TheV lower end ot the re bridge gratebars 10 has a recess 25 out therein for engagement with a iillet 26 ot the portion 9 of the dead plate supporting the said ends, whereby the said grate bars are maintained more securely in the proper position.

It is` to bev observed that the shape ot' the cross section et' the bars of the two grates results in producing au intensiiied draught due to the compression of the air resulting` trom the gradually .narrower section ot' the air passages between the lateral inclined races ot the adjacent grate-bars.

I claim:

1. rn a grate-structure for steam boilers, the combination ot: a horizontal grate-plate comprising grate-bar bearers and a plurality ot removable and interchangeable longitudinahy waved grate-bars ot' cuneit'orm cross section arranged side to side and resting at their ends on the said'grate-lnir bearers; a quarte ircular lire bridge grate comprising a plura ot removable and interchangeable curved grate-bars arranged side to side "l hi-iving out away portions forming corami rugatious. along` a portion of the lenfrth ot' their sides and a series oit' recesses vrormed in their edges close to their upper ends in such manner as to constitute by their juxtaposition apertures tor the passage ot cooling air; a horizontal dead plate arranged under said .fire bridge grateand cast with a portion adapted to torni a support :tor the lower ends ott the tire bridge grate-bars; a supporting plate arranged substantially at right angles to the said dead plate and extending under the upper ends of said grate-bars: and hand controlled means tor locking the last-named grate-bars in position; substantiall as described.

in a grate-structure tor steam boilers the combination ot: a horizontal grate-plate comprising grate-bar bearers and a plurali ot removable and interchangeable longitudinally waved grate-bars ot cuncitorm cross section arranged side to side and resting at their ends on the said grate-bar hearers: a Quarter-circular tire bridge grate comprising a plurality ot removable and interchangeable curved grate-bars arranged side to side and having cut away portions forming corrugations along a portion ot the length or their sides and a series oft recesses termed in their edges close to their upper ends in such manner as to constitute by their juxtaposition apertures 'for the passage ot cooling air, said grate-bars having a cross section of a width increasing graduail)Y in an upward direction vfor the greater part ot their height and iu notably accentuated proportions at the top; a supporting plate arranged substantially at right angles to the said. dead plate and extending under the upper ends et said grate-bars; and hand controlled means 'tor locking the last-named grate-bars in position; substantially as dcscribed.

3. 1n a grate-structure for steam boilers, the combination ot: a horizontal grate-plate comprising grate-bar bearers and a plurality ot removable and interchangeable longitudinally waved grate-barsA oity cuneitorm cross section arranged Side t0 side and resting at their ends on the said grate-bar bearers; a quarter-circular fire bridge grate comprising a plurality of removable and interchangeable curved grate-bars arranged side to side and having cut away portions forming corrugations along a portion of the length of their sides and a series of recesses formed in their edges close to their upper ends in such manner as to constitute by their juxtaposition apertures for the passage of cooling air, said grate-bars having a recess cut in their lower ends; a horizontal dead plate arranged under said fire bridge grate and cast with a portion shaped to support the lower ends of the last-named grate-bars and including a llet adapted to engage in the recesses cut in the said lower ends; a supporting plate arranged substantially at right angles to the said dead plate and extending under the upper ends of said grate-bars; and hand controlled means for locking the lastnamed grate-bars in position; substantially as described.

4. In a grate-structure for steam boilers, the combination of: a horizontal grate-plate comprising greats-bar bearers and a plurality of removable and interchangeable longitudinally waved grate-bars of cuneiform cross section arranged side to side and resting at their ends on the said grate-bar bearers; a quarter-circular fire bridge grate comprising a plurality of removable and interchangeable curved grate-bars arranged ends in such manner as to constitute by their juxtaposition apertures for the passage of cooling air, said grate bars having a recess out in the web-portion thereof at their upper ends; a horizontal dead plate arranged under said fire bridge grate and cast with a portion adapted to form a support for the lower ends of the fire bridge grate-bars; a supporting plate arranged under the upper ends of the said grate-bars substantially at right-angles to the said dead plate and having a longitudinal slot cut therein close to its upper edge; and means for locking the lastnanied grate-bars in position, comprising a lat locking bar passing through said slot and a set of suitably arranged rod-connections for operating said locking bar from the furnace front for engagement in or disengagement from the aforesaid recesses of the upper ends of the said last-named'gratebars; substantially as described.

In testimony whereof I signed hereunto niy naine in the presence of two subscribing witnesses.

EDGARD DUPONT. lVitnesses y E. CUYFUL, M. BLAIN. 

